Leave it to a veteran of “The Ultimate Fighter” to step up for fill-in duties for the show’s next live finale.

Following Wednesday’s loss of headliner and head coach Shane Carwin (12-2 MMA, 4-2 UFC) due to a knee injury, “TUF 10″ vet Matt Mitrione (5-1 MMA, 5-1 UFC) has stepped in as his replacement.

He now meets Roy Nelson (17-7 MMA, 4-3 UFC) next month in the headliner of The Ultimate Fighter 16 Finale.

Officials today announced verbal agreements are in place for the fight. Mitrione was slated to fight Philip De Fries (9-1 MMA, 2-1 UFC) at the year-end UFC 155 event. However, according to officials, De Fries will get a new opponent.

The TUF 16 Finale takes place Dec. 15 at The Joint at Hard Rock Hotel & Casino in Las Vegas. The main card airs on FX. FUEL TV and Facebook carry the prelims.

Carwin and Nelson coached opposite each other on the 16th season of “TUF,” which taped over the summer and currently airs on Friday nights on FX. The head coaches were expected to meet in the traditional season-ending fight, but UFC President Dana White announced Carwin’s knee injury and withdrawal on Wednesday.

In his place steps Mitrione, who suffered his first career loss with a unanimous-decision defeat to Cheick Kongo at UFC 137. Prior to that, he won his first five pro fights, all in the UFC. Four of the former NFL player’s wins came via knockout.

Nelson, meanwhile, most recently knocked out Dave Herman at UFC 146. The “TUF 10″ champion, who never fought Mitrione on the reality show, is 2-1 since back-to-back decision losses to now-champ Junior Dos Santos and former titleholder Frank Mir.